Game state synchronization and restoration across multiple devices

ABSTRACT

Some examples include backing up and restoring a game application state across multiple devices. A distributed system may run an instance of a game application at a first electronic device, determine a backup event that occurs in the first electronic device, wherein the backup event suggests a backup of application state data and the application state data represent an application state of the game application at the backup event, and transmit the application state data of the game application to a remote storage service in response to the backup event. A second electronic device may retrieve the application state data from the remote storage service and restore the game application state.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 14/221,161, entitled “GAME STATE SYNCHRONIZATION AND RESTORATIONACROSS MULTIPLE DEVICES”, filed Mar. 20, 2014, issued as U.S. Pat. No.9,606,782, which is a U.S. non-provisional patent application thatclaims the benefit of U.S. provisional patent application No.61/804,134, entitled “OPERATING SYSTEM AND DEVICE INTEGRATED WITH CLOUDCOMPUTING FUNCTIONALITIES,” filed on Mar. 21, 2013, which areincorporated by reference herein in their entirety.

FIELD OF THE INVENTION

At least one embodiment of the present invention pertains to cloudcomputing and, more particularly, to automatic backup and restoration ofapplication states across multiple devices that use cloud storage by adistributed system.

BACKGROUND

Application state data is data used to record the running status of acomputer application. One example of application state data is a gamesave for a game application. A game save is a piece of digitally storedinformation related to the progress of a user operating the gameapplication. The game save can be reloaded later so that the user cancontinue where he stopped. The user instructs the game application togenerate a game save (i.e., save the game) to prevent the loss ofprogress in the game, especially when he is interrupted or is ending agame session.

Sharing and backing up game saves among users has been common for manyyears. Originally, users could help each other unlock features in a gameapplication by swapping memory cards with game saves. With the growingpopularity of the Internet, users started to upload their game savesfrom their devices to Internet servers. By downloading a game save froman Internet server, a user can continue the progress of the game on thedevice on which he played the game or on another device, such as acomputer, game console, or smart phone. However, to achieve the goal ofcontinuing the progress on another device, the user deliberately needsto instruct the device to save the game progress (i.e., game save) andupload the game save to a server or a memory card. Then the user mustdownload the game from the server or the memory card to the other deviceand, finally, instruct the other device to load the game save. Thisprocess is tedious and requires many user interventions. Furthermore,this process only works for game applications that are specificallydesigned with game saving functionalities.

SUMMARY

Techniques introduced here provide an automatic mechanism for backing upand restoring application state data across multiple devices. Inaccordance with the techniques introduced herein, a first instance of acomputer application is run by a distributed system, on the firstelectronic device and a backup event is determined to occur in the firstelectronic device. The backup event suggests a backup of applicationstate data, and the application state data represents an applicationstate of the computer application at the backup event. The techniquefurther includes a process by which the distributed system stores statedata of the first instance of the application and detects a seconddevice upon which the application is installed. The distributed systemsends the state data to the second device and launches a second instanceof the application on the second device. The distributed system thensynchronizes the second instance of the application on the second devicewith the state data received and resumes the second instance of theapplication on the second device after the synchronization is completed.

The backup proceeds automatically in the background of the operatingsystem of the device and is transparent to the user, as well as theapplication. The user can restore the application state of theapplication running on the same device or on another device where thestate of the application has been backed up. The application statebackup and restoration can be achieved at the operating system level ofthe devices. There is no special treatment or design needed for thecomputer application itself. Any computer application capable of runningon such an operating system can take advantage of the application statebackup and restore functionality. The distributed system can spreadamong smart phones, tablet computers, desktop computers, and othercomputing devices.

A distributed system is a collection of independent computing elementsstored in a distributed manner that appears to its users as a singlecoherent system. The function of the single coherent system can beproduced by software. The distributed system can spread across a largegeographic area since the components of the distributed system can belinked by wired or wireless networks. The distributed system can havebetter performance compared to a single computing unit and have betterfault tolerance than a single computing unit.

The distributed system can enable multiple computing devices tointeroperate with one another. In this way, the distributed system canmanage multiple computing devices as a single entity. The givenapplication can then be used by any of the computing devices whenexecuting a given application through the distributed system.

For instance, the technology of the distributed system enables the useof user interfaces from a plurality of computing devices to bothinteract with the distributed system (e.g., through a homescreen/desktop of the distributed system) and to also install anapplication on the distributed system. The application is installed onan application layer of the distributed system, where any of thecomputing devices being managed by the distributed system can invoke theapplication installed on the application layer of the distributedsystem. Thus, a separate installation of the application on each of thecomputing devices is not required to execute the application through anyof the computing devices if the application is installed through thedistributed system managing the computing devices.

In one embodiment, an instance of the distributed system is executedusing the hardware resources of the multiple computing devices andmanages the hardware resources of all the computing devices as a singleentity. The various components of the distributed system (e.g., the filesystem of the distributed system) are stored across the hardwareresources of the multiple computing devices. For instance, the dataassociated with a file system of the distributed system is stored acrossthe memory resources of the various computing devices. The distributedsystem gathers any required data associated with the file system fromacross the computing devices when the data are needed for access to thefile system.

Other aspects of the technology introduced here will be apparent fromthe accompanying figures and from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example system for application statesynchronization between electronic devices.

FIG. 2 illustrates an example of an application state synchronizationprocess across multiple electronic devices.

FIG. 3 illustrates an example operating system of an electronic device.

FIG. 4 illustrates an example of an application state data of a computerapplication collected by an operating system.

FIG. 5 illustrates an example of an application state synchronizationprocess based on a user-defined synchronization scheme.

FIG. 6 illustrates an example of multiple application state backup andrestoration processes where a user can select whichever applicationstate the user wants to restore.

FIG. 7 illustrates an example of an application state synchronizationprocess when an update occurred at a remote storage server.

FIG. 8 is a high-level block diagram showing an example of thearchitecture of a computer server, which may represent any computerrunning the database management system described herein.

DETAILED DESCRIPTION

References in this specification to “an embodiment,” “one embodiment,”or the like mean that the particular feature, structure, orcharacteristic being described is included in at least one embodiment ofthe present invention. However, occurrences of such phrases in thisspecification do not all necessarily refer to the same embodiment.

A method of application state synchronization across devices isdescribed herein. For example, a user plays a game on a smart phone thenstops playing and turns off the screen of the smart phone. The state ofthe game application is synchronized between his smart phone and otherelectronic devices via a cloud system. The user can pick up a tabletcomputer and continue to play the game from wherever the user left off.The synchronization is not necessarily directly triggered by userintervention. For instance, the synchronization can be automaticallytriggered when the screen of the smart phone is turned off or the usercloses the game on the smart phone. The synchronization proceedsautomatically in the background, transparent to the user. Furthermore,the cloud system can analyze a variety of information, including thedevice profile, user profile, and user history to determine how tooptimize when the state is synchronized and to which device the state issynchronized.

FIG. 1 illustrates an example system for application statesynchronization between electronic devices. The system includes a cloudstorage service 110 configured to store state data for applications. Inone embodiment of the invention, the cloud storage service 110 is astorage cluster having computer nodes interconnected with each other bya network. The storage cluster communicates with other electronicdevices via the Internet. The cloud storage service 110 contains storagenodes 112. Each of the storage nodes 112 contains one or more processors114 and storage devices 116. The storage devices include optical diskstorage, RAM, ROM, EEPROM, flash memory, phase change memory, magneticcassettes, magnetic tapes, magnetic disk storage or any other computerstorage medium which can be used to store the desired information.

In one embodiment, a cloud synchronization interface 120 receives datato be stored in the cloud storage service. The cloud synchronizationinterface 120 includes network communication hardware and networkconnection logic to receive the information from electronic devices. Thenetwork is a local area network (LAN), wide area network (WAN) or theInternet. The cloud synchronization interface 120 may include a queuingmechanism to organize the received synchronization data to be stored inthe cloud storage service 110. The cloud synchronization interface 120communicates with the cloud storage service 110 to send requests to thecloud storage service 110 for storing and retrieving application statedata.

An electronic device 130 includes an operating system 132 to manage thehardware resources of the electronic device 130 and provide services forrunning computer applications 134. The computer application 134 storedin the electronic device 130 requires the operating system 132 to run onthe device 130. The electronic device 130 can backup application statesof the computer applications 134 to the cloud storage service 110. Theelectronic device 130 includes at least one local storage device 138 tostore the computer applications, application data, and user data. Theelectronic device 130 can synchronize the application state data withthe cloud storage service 110 via the cloud synchronization interface120. The electronic device 130 or 140 can be a desktop computer, alaptop computer, a tablet computer, an automobile computer, a gameconsole, a smart phone, a personal digital assistant, or otherelectronic devices capable of running computer applications, ascontemplated by a person having ordinary skill in the art.

In one embodiment, the computer applications 134 stored in theelectronic device 130 include applications for general productivity andinformation retrieval, including email, calendar, contacts, and stockmarket and weather information. The computer applications 134 can alsoinclude applications in other categories, such as mobile games, factoryautomation, GPS and location-based services, banking, order-tracking,ticket purchases or any other categories as contemplated by a personhaving ordinary skill in the art.

The operating system 132 of the electronic device 130 includes a statesynchronization module 136 to backup application state information fromthe local storage. The state synchronization module 136 keeps theapplication state data from the electronic device 130 in synchronizationwith the cloud storage service 110 and other devices.

In one embodiment, another electronic device 140 synchronizes theapplication state with the cloud storage service 110. The electronicdevices 130 and 140 can synchronize the application states between eachother via the cloud storage service 110. For instance, the electronicdevice 130 can synchronize the application state of a computerapplication to the cloud storage service 110. The cloud storage service110 communicates with the electronic device 140 to detect whether theelectronic device 140 also contains this computer application andwhether the application state of this computer application is notupdated on the electronic device 140. In turn, the cloud storage service110 sends the application state data to the electronic device 140. Thus,the application state of this computer application is synchronizedbetween the electronic devices 130 and 140.

In one embodiment, the synchronization for backups from the electronicdevices 130 and 140 to the cloud storage service 110 takes place on aconfigurable periodic basis, such as a predetermined time of day. Thescheduled synchronization can also check for updates that can be sentfrom the cloud storage service 110 to the electronic devices 130 and140.

In one embodiment, another type of synchronization is triggered when anevent occurs on the electronic device 130 or 140, and then the statesynchronization module can initialize the application state datasynchronization with the cloud storage service 110. The triggeredsynchronization does not need any intervention from the user. Forinstance, a user turns off the screen of the electronic device 130triggering an application state data synchronization with the cloudstorage service 110, as well as other electronic devices. However, theuser does not need to specifically instruct the device to synchronize;the user does not even need to realize that the synchronization occurs.

In one embodiment, the backup event is any of the following: the screenof the electronic device being turned off; the instance of the computerapplication being closed; the instance of the computer application beingpaused; the instance of the computer application having been runcontinuously for a preconfigured period of time; the instance of thecomputer application being switched by another application; the instanceof the computer application being switched from the foreground to thebackground of the operating system; the battery level of the electronicdevice being below a preconfigured value; the electronic device turningoff; the electronic device switching to standby mode; the clock of theelectronic device reaching a preconfigured time of day; and theelectronic device being in a preconfigured location.

In one embodiment, the synchronization is a delta synchronization wherethe electronic device 130 or 140 detects a change (i.e., delta) ofapplication state data and only the changed data or difference issynchronized to the cloud storage device 110.

Any electronic device running an operating system having the statesynchronization module initializes the application statesynchronization. In addition, the cloud storage service 110 can alsoinitialize the application state synchronization. In one embodiment, thecloud storage service 110 may analyze the electronic devices todetermine which device is to be synchronized and what state data ofwhich application is to be synchronized.

FIG. 2 illustrates an example of an application state synchronizationprocess across multiple electronic devices. At step 205, a cloud storagesystem identifies a plurality of electronic devices capable ofsynchronizing application state data with the cloud storage system. Theelectronic devices may be capable of communicating with the cloudstorage system via a network, such as the Internet, a WiFi Network, or acellular phone network. At step 210, one of the identified electronicdevices runs an application.

At step 215, a backup event is determined to occur on the electronicdevice. The operating system of the electronic device automaticallydetermines the backup event without any intervention, instruction, orawareness from the user. There is no need for a sync button, a syncgesture, a sync menu item, or a sync command In other words, theoperating system of the device determines whether to initiate a backupevent. For instance, the operating system may recognize an event of thescreen being turned off as a backup event. The operating system may alsorecognize an event of a running application being closed or beingswitched by another application as a backup event. The operating systemmay further recognize an event of a system standby as a backup event.The operating system of the device can determine other types of backupevents as contemplated by a person having ordinary skill in the art.

Once the operating system detects a backup event, the operating systemof the electronic device uploads the application state data of thecomputer application onto the cloud storage system at step 220. Theoperating system of the device decides to immediately upload theapplication state data after the backup event or start the upload at acertain amount of time after the backup event. For instance, if theelectronic device detects that there is another electronic device fromthe same user in a very close proximity, the operating system of thedevice may decide to start the upload, assuming a high possibility thatthe user will start using the other device soon. In another embodiment,the electronic device may decide to start the upload at a certain timeof day or at certain location. For instance, the electronic device maydecide to start the upload at midnight and at the user's home(determined by GPS location or WiFi location) so that the upload of theapplication state data does not intervene with the normal operation ofthe device.

In one embodiment, the developer of the computer application does notspecifically need to write any implementation for uploading theapplication state data. For example, there are no API calls embedded inthe computer application for the application state data. The statesynchronization module of the operating system is responsible formonitoring, collecting, and uploading the application state data. Insome embodiments, the state synchronization module compares the currentapplication state on the device and the application state already storedin the cloud storage service. If the current application state is newerthan the application state stored in the cloud storage service, thestate synchronization module determines the difference (i.e., delta)between the current application state data and the application statedata stored in the cloud storage service. In this way, the statesynchronization module only needs to upload the difference to the cloudstorage service. The cloud storage service is responsible forincorporating the difference into the application state data alreadystored.

At step 225, the cloud storage system analyzes the device profile, userprofile and user history to determine to which device the state issynchronized. For instance, in one embodiment, the cloud storage systemrecognizes the various devices that the same user is using (e.g., thedevices which have established the user's user account). In anotherembodiment, the analysis is based on usage pattern. For example, thecloud storage service can determine whether to synchronize theapplication state to devices that the user has been frequently usingduring a specific time period (e.g., a week), or the cloud storageservice can determine whether to synchronize the application state todevices on which the user has been running that computer application. Inyet another embodiment, the analysis is based on a proximity algorithm.For example, the cloud storage service can determine to synchronize theapplication state to devices that are physically close to the device instep 210. The proximity may be determined by GPS locations, WiFi networklocations, cellular networking locations or the combination thereof. Instill another embodiment, the analysis is based on the types ofapplications installed on the devices. For example, the cloud storageservice can determine to synchronize the application state to devicesthat have instances of that application installed or devices that havesimilar applications installed. Furthermore, the analysis can bedetermined by a combination of the above techniques, as well as anyother device or user information as contemplated by a person havingordinary skill in the art.

The same types of analysis disclosed in the previous paragraph are usedin determining the priority of synchronization. For instance, if thereis an application state data synchronization for multiple applicationsin the cloud storage service, the cloud storage service may determinewhether to synchronize the state data for one application because theuser has been frequently using that application during a recent timeperiod (e.g., a week). In one embodiment, the cloud storage servicedecides a priority list, including a reference to the application statedata for the computer application, wherein the priority list regulatesthe order of transmitting the application state data for the computerapplication and data for other applications based on the analysis of theuser profile and the hardware profiles of the electronic devices.

In some embodiments, the analysis is performed after the cloud storagesystem receives application state data from a device. In some otherembodiments, the analysis can be performed before the cloud storagesystem receives any application state data or before the backup eventoccurs.

At step 230, the cloud storage system sends the application state datato one or more devices that are identified by the analysis. Theidentified devices receive the application state data. Therefore, theinstances of the application running on the devices are synchronizedwith the most up-to-date state. A user can run an instance of theapplication on any of these devices, and the instance of the applicationresumes from the most up-to-date state. In one embodiment, the cloudstorage system further sends an instruction to each of the identifieddevices to run an instance of the computer application by resuming theapplication state at the backup event at step 235.

In one embodiment, the application state data of a computer applicationmay include application memory data, application local storage data,hardware configuration data, and user account configuration data. Thestate synchronization module of the operating system is capable ofcollecting this data and uploading the data as included in theapplication state data to the cloud storage service. Based on theapplication state data, an operating system of another electronic devicecan recreate the same environment and status of the application on theother electronic device.

In some embodiments, the electronic devices are capable of synchronizingapplication state data between each other via a network, such as a WiFinetwork, a Bluetooth network, or a cellular phone network. Each of theelectronic devices contains a network component configured tosynchronize the application state data with another electronic device.

FIG. 3 illustrates an example of an operating system of an electronicdevice, according to one embodiment. The operating system 300 includes akernel 304. The kernel 304 provides interfaces to hardware of theelectronic device for the computer applications running on top of thekernel 304 and supervises and controls the computer applications. Thekernel 304 isolates the computer applications from the hardware. Thekernel 304 may include one or more intervening sources that can affectexecution of a computer application. In one embodiment, the kernel 304includes a network I/O module 306, a file I/O module 308,multi-threading module 310, user input 314, system interrupts 316, andshared memory access 318.

A state synchronization module 330 runs on top of the kernel 304. Thestate synchronization module 330 monitors the information from theintervening sources of the kernel 304 and records state data accordingto the information. In the example of FIG. 3, a computer application 340includes a binary executable code 342 that can run in the background ofthe operating system 300. The computer application 340 can furtherinclude static and dynamic libraries 344 that are referenced by thebinary executable code 342 while an application is running In oneembodiment, the state synchronization module 330 runs in a user spacefile system (e.g., FUSE) in the background of a Linux kernel. In anotherembodiment, the state synchronization module 330 runs in a kernel filesystem.

FIG. 4 illustrates an example of an application state data of a computerapplication collected by an operating system, according to oneembodiment. The application state data 400 of a computer application mayinclude application memory data 402, application local storage data 404,hardware configuration data 406, and user account configuration data408. In some other embodiments, the application state data can be all orany combination of fields 402, 404, 406 and 408. When the computerapplication is running, the state information in the memory section(i.e., the application memory data 402) allocated for the application isupdated by the running application. The state synchronization module ofthe operating system monitors the application memory data 402 anduploads the data to a cloud storage service in response to the backupevent. Furthermore, the computer application can update certain data onthe local storage of the electronic device. The state synchronizationmodule of the operating system can include the application local storagedata 404 synchronized with the application state data 400. In someembodiments, the electronic device includes a memory device (e.g., flashmemory) as both the memory and the local storage. Therefore, theapplication memory data 402 and application local storage data 404 canbe one section of data in the memory device of the electronic device.

The application state data 400 may further include hardwareconfiguration data 406. For instance, the state synchronization modulemay record the current device's volume level and screen brightness levelwhen the application is running. The device's volume level and screenbrightness level are recorded as part of the hardware configuration data405 and are uploaded to the cloud storage service. Therefore, afteranother device is synchronized with the application state data andresumes running the application, the other device automatically adjuststhe volume level and screen brightness level to match the level on theprevious device. Moreover, the application state data 400 may includeuser account configuration data 408. The user account configuration data408 may include the user's preferences and choices regarding thecomputer application and the operating system environment for runningthe computer application. For instance, the user account configurationdata 408 may include information about the user's language preference.Assuming the computer application is a game that supports both Englishand Chinese languages and the user has selected English as the preferredlanguage, the state synchronization module records the user's languagepreference as a part of the user account configuration data 408. Theuser account configuration data 408 is synchronized to another devicevia the cloud storage service. When the other device resumes running theapplication, the application will use the English language for the gameinterface, as indicated by the user account configuration data 408.

In some embodiments, a user can define a synchronization scheme tocontrol how and when the synchronization process occurs. FIG. 5illustrates an example of an application state synchronization processbased on a user defined synchronization scheme. At step 505, a cloudstorage service receives an instruction of a synchronization scheme froma user. The synchronization scheme includes rules of how and when thesynchronization process performs. For example, in one embodiment, thesynchronization scheme can define a synchronization rule between twoelectronic devices, i.e., a smart phone and a tablet computer, forapplication state of a game application. The synchronization rulespecifies that one of the electronic devices attempts to synchronize theapplication state to the other device as soon as the game application isclosed or the screen of the device being turned off.

Assuming a smart phone is the current device running the gameapplication, at step 510, the operating system of the smart phone, apart of the distributed system, checks whether the game application ispaused by the user. If the game application is paused, the processcontinues to step 520. Otherwise, at step 515, the process, by the meansof the distributed system, checks whether the screen of the smart phoneis turned off. If the screen is turned off, the process continues tostep 520. Otherwise, the process goes back to check the status in apredetermined time period by the means of the distributed system, as insteps 510.

At step 520, the smart phone uploads the application state data of thegame application to the cloud storage system, a part of the distributedsystem. The schedule of the uploading can depend on the type and speedof the connection between the smart phone and the cloud storage system.For instance, the schedule can be configured so that the uploading isdelayed until a WiFi connection is available to avoid using a cellulardata connection (e.g., 3G or LTE). At step 525, the cloud storage systemreads the synchronization scheme defined by the user. At step 530, thecloud storage system checks whether a second device (i.e., a tabletcomputer) is currently connected with the cloud storage system. If thetablet computer is connected with the cloud storage system, the systemsends the application state data to the tablet computer according to thesynchronization scheme at step 535. Otherwise, the cloud storage systemcontinues to check the connection with the tablet computer on a periodicbasis.

At step 540, when the user starts to use the tablet computer, the tabletcomputer runs an instance of the game application. At step 550, thedistributed system checks whether the user pauses the application of thegame application and waits for the synchronization process to befinished. If the user pauses the application, the distributed system canwait for the synchronization, and then, in step 560, the distributedsystem can resume the application state recorded in the synchronizedapplication state data at the second device.

FIG. 6 illustrates an example of multiple application state backup andrestoration processes where a user can select which application statehe/she wants to restore to. At step 605, the distributed system runs afirst instance of an application on the first electronic device. Thefirst electronic device can be a smart phone, a tablet, or any othercomputing device. The first instance of the application is communicatingwith a cloud storage system that is a part of the distributed system. Atstep 610, the distributed system runs a second instance of anapplication on a second electronic device. The second electronic devicecan be a smart phone, a tablet, or any other computing device. Thesecond instance of the application is communicating with a cloud storagesystem that is a part of the distributed system.

At step 620, the first electronic device uploads the application statedata of the computer application to a remote storage service. The remotestorage service can be a cloud computing service. Alternatively, theremote storage service belongs to a cloud storage service cluster. Thefirst electronic device is capable of transmitting the application statedata to the remote storage service via a network, which can include theInternet, a WiFi network, or a cellular phone network. In oneembodiment, the first electronic device can immediately transmit theapplication state data of the computer application to a remote storageservice in real time without a substantial delay.

The application state data of the computer application can betransmitted to the remote storage service at a preconfigured time of dayor when the first electronic device is at a preconfigured location. Insome embodiment, the application state data of the computer applicationcan be transmitted to the remote storage service based on a sync scorethat would have an optimization scale built in. The optimization scalecan be calculated based on a predetermined formula with inputs such asnetwork speed, location of the devices, number of the devices, time ofday. Alternatively, the application state data of the computerapplication can be transmitted to the remote storage service at ascheduled time depending on the type and speed of the connection betweenthe first electronic device and the remote storage service in responseto the backup event. The schedule can be preconfigured to avoid using acellular data connection so that the transmitting is delayed until aWiFi connection is available. The backup can be incremental. Forinstance, the difference between the application state data of thecomputer application and previously transmitted application state datacan be transmitted to a remote storage service in response to the backupevent.

At step 630, the second electronic device uploads the application statedata of the computer application to a remote storage service. The remotestorage service can be a cloud computing service. Alternatively, theremote storage service can belong to a cloud storage service cluster.The second electronic device is capable of transmitting the applicationstate data to the remote storage service via a network, which caninclude the Internet, a WiFi network, or a cellular phone network. Inone embodiment, the second electronic device can immediately transmitthe application state data of the computer application to a remotestorage service in real time without a substantial delay.

The application state data of the computer application can betransmitted to the remote storage service at a preconfigured time of dayor when the second electronic device is at a preconfigured location.Alternatively, the application state data of the computer applicationcan be transmitted to the remote storage service at a scheduled timedepending on the type and speed of the connection between the secondelectronic device and the remote storage service. The schedule can bepreconfigured to avoid using a cellular data connection so that thetransmitting is delayed until a WiFi connection is available. The backupcan be incremental. For instance, the difference between the applicationstate data of the computer application and the previously transmittedapplication state data can be transmitted to a remote storage service inresponse to the backup event.

At step 640, the distributed system can notify a user that two instancesof the application state data have been saved. This notification can besent through a network, such as a WiFi network or a cellular phonenetwork. At step 650, the distributed system can allow the user to electa final application state data out of the first instance of theapplication state data and the second instance of the application statedata. In some embodiments, the user can make the selection through thefirst electronic device. In some embodiments, the user can make theselection through the second electronic device. In some embodiments, theuser can make the selection through a terminal coupled to thedistributed system.

At step 660, the cloud storage system checks whether a third device(i.e., a desktop computer) is currently connected with the cloud storagesystem. If the desktop computer is connected with the cloud storagesystem, at step 670, the system sends the application state data to thedesktop computer. Otherwise, the cloud storage system continues to checkthe connection with the desktop computer on a periodic basis. At step680, when the user starts to use the desktop computer, the desktopcomputer starts to run an instance of the game application. At step 690,the distributed system checks whether the user pauses the application ofthe game application and waits for the synchronization process to befinished. If the user pauses the application, the distributed system canwait for the synchronization, and then in step 695, the distributedsystem can resume the application state recorded in the synchronizedapplication state data at the desktop computer.

FIG. 7 illustrates an example of an application state synchronizationprocess when an update occurred at a remote storage server. At step 705,the distributed system runs a first instance of an application on thefirst electronic device. The first electronic device can be a smartphone, a tablet or any other computing device. The first instance of theapplication is communicating with a cloud storage system that is a partof the distributed system. At step 710, the distributed system checkswhether the remote server has been updated. If the remote server hasbeen updated, at step 715, the distributed system checks whether theapplication at the first device can be safely shut down without crashingthe operating system of the first device. If the application can besafely shut down and the remote server has been updated, at step 720,the distributed system shuts down the application that runs on the firstdevice. If the remote server has not been updated or the applicationcannot be safely shut down, the distributed system will check step 710and 715 again.

At step 725, the distributed system can restart the application at thefirst device and sync with the remote server. At step 730, thedistributed system checks whether a second device is connected with thecloud storage system. If there is a second device connected with thecloud storage system, at step 735, the distributed system can send theapplication state data to the second device. At step 740, thedistributed system can run an instance of the game application at thesecond device. At step 760, the distributed system can resume theapplication state recorded in the synchronized application state data onthe second device.

FIG. 8 is a high-level block diagram showing an example of thearchitecture of a computer, which may represent any electronic device orany server within a cloud storage service as described herein. Theserver 800 includes one or more processors 810 and memory 820 coupled toan interconnect 830. The interconnect 830 shown in FIG. 8 is anabstraction that represents any one or more separate physical buses,point-to-point connections, or both connected by appropriate bridges,adapters, or controllers. The interconnect 830, therefore, may include,for example, a system bus, a Peripheral Component Interconnect (PCI) busor PCI-Express bus, a HyperTransport or industry standard architecture(ISA) bus, a small computer system interface (SCSI) bus, a universalserial bus (USB), IIC (I2C) bus, or an Institute of Electrical andElectronics Engineers (IEEE) standard 1394 bus, also called “Firewire.”

The processor(s) 810 is the central processing unit (CPU) of the server800, and thus, controls the overall operation of the server 800. Incertain embodiments, the processor(s) 810 accomplishes this by executingsoftware or firmware stored in memory 820. The processor(s) 810 may be,or may include, one or more programmable general-purpose orspecial-purpose microprocessors, digital signal processors (DSPs),programmable controllers, application specific integrated circuits(ASICs), programmable logic devices (PLDs), trusted platform modules(TPMs), or the like, or a combination of such devices.

The memory 820 is, or includes, the main memory of the server 800. Thememory 820 represents any form of random access memory (RAM), read-onlymemory (ROM), flash memory, or the like, or a combination of suchdevices. In use, the memory 820 may contain a code 870, containinginstructions according to the techniques disclosed herein.

Also connected to the processor(s) 810 through the interconnect 830 area network adapter 840 and a storage adapter 850. The network adapter 840provides the server 800 with the ability to communicate with remotedevices over a network and may be, for example, an Ethernet adapter orFibre Channel adapter. The network adapter 840 may also provide theserver 800 with the ability to communicate with other computers. Thestorage adapter 850 allows the server 800 to access a persistent storageand may be, for example, a Fibre Channel adapter or SCSI adapter.

The code 870 stored in memory 820 may be implemented as software and/orfirmware to program the processor(s) 810 to carry out actions describedabove. In certain embodiments, such software or firmware may beinitially provided to the server 800 by downloading it from a remotesystem through the server 800 (e.g., via network adapter 840).

The techniques introduced herein can be implemented by, for example,programmable circuitry (e.g., one or more microprocessors) programmedwith software and/or firmware, by special-purpose hardwired circuitry,or by a combination of such forms. Special-purpose hardwired circuitrymay be in the form of, for example, one or more application-specificintegrated circuits (ASICs), programmable logic devices (PLDs),field-programmable gate arrays (FPGAs), etc.

Software or firmware for use in implementing the techniques introducedhere may be stored on a machine-readable storage medium and may beexecuted by one or more general-purpose or special-purpose programmablemicroprocessors. A “machine-readable storage medium”, as the term isused herein, includes any mechanism that can store information in a formaccessible by a machine (a machine may be, for example, a computer,network device, cellular phone, personal digital assistant (PDA),manufacturing tool, any device with one or more processors, etc.). Forexample, a machine-accessible storage medium includesrecordable/non-recordable media (e.g., read-only memory (ROM); randomaccess memory (RAM); magnetic disk storage media; optical storage media;flash memory devices; etc.).

The term “logic”, as used herein, can include, for example, circuitryprogrammed with specific software and/or firmware, special-purposehardwired circuitry, or a combination thereof.

In addition to the above mentioned examples, various other modificationsand alterations of the invention may be made without departing from theinvention. Accordingly, the above disclosure is not to be considered aslimiting, and the appended claims are to be interpreted as encompassingthe true spirit and the entire scope of the invention.

What is claimed:
 1. A computer-implemented method comprising: running,by a distributed system, a first instance of an application at a firstdevice; determining, by the distributed system, a sync event that occursin the first device; storing, by the distributed system, a state data ofthe first instance of the application, wherein the storing comprisestransmitting a difference between a current state data of the firstinstance of the application and a previously stored state data of thefirst instance of the application in response to the sync event;determining, by the distributed system, a second device to which thestate data is to be synchronized; sending, by the distributed system,the state data to the second device; and synchronizing, by thedistributed system, a second instance of the application at the seconddevice with the state data, wherein the second instance of theapplication is paused during the synchronizing.
 2. Thecomputer-implemented method of claim 1, wherein the sync event comprisesat least one: of a closure of the application; a pause of theapplication; continuous operation of the application for a preconfiguredperiod of time; or a switch from the application to an anotherapplication.
 3. The computer-implemented method of claim 1, furthercomprising resuming, by the distributed system, the second instance ofthe application at the second device after the synchronizing iscompleted.
 4. The computer-implemented method of claim 1, wherein thefirst device is a smartphone.
 5. The computer-implemented method ofclaim 1, wherein the second device is a tablet computer.
 6. Thecomputer-implemented method of claim 1, wherein the state data of thefirst instance of the application is stored in a cloud storage server.7. The computer-implemented method of claim 1, wherein a third instanceof the application runs on the second device when the sync event occurs.8. The computer-implemented method of claim 7, further comprising:closing, by the distributed system, the third instance of theapplication at the second device; and starting, by the distributedsystem, the second instance of the application at the second device. 9.A computer-implemented method comprising: identifying, by a distributedsystem, a plurality of electronic devices capable of synchronizingapplication state data; running, by the distributed system, a firstinstance of an application at a first device of the plurality of theelectronic devices; running, by the distributed system, a secondinstance of the application at a second device of the plurality of theelectronic devices; determining, by the distributed system, a first syncevent that occurs in the first device; storing, by the distributedsystem, a first state data of the first instance of the application;determining, by the distributed system, a second sync event that occursin the second device; storing, by the distributed system, a second statedata of the second instance of the application; receiving, by thedistributed system, a selection of one of the first state data and thesecond state data as a final state data; determining, by the distributedsystem, a third device to which the final state data is to besynchronized; and sending, by the distributed system, the final statedata of the application to the third device.
 10. Thecomputer-implemented method of claim 9, wherein the first sync eventcomprises at least one of: a closure of the application at the firstdevice; a pause of the application at the first device; continuousoperation of the application for a preconfigured period of time at thefirst device; or a switch from the application to an another applicationat the first device.
 11. The computer-implemented method of claim 9,wherein the second sync event comprises at least one of: a closure ofthe application at the second device; a pause of the application at thesecond device; a continuous operation of the application for apreconfigured period of time at the second device; or a switch from theapplication to an another application at the second device.
 12. Thecomputer-implemented method of claim 9, wherein the first device is asmartphone.
 13. The computer-implemented method of claim 9, wherein thesecond device is a tablet computer.
 14. The computer-implemented methodof claim 9, wherein the first state data of the first instance of theapplication is stored in a cloud storage server.
 15. A distributedsystem comprising: a memory; and at least one processor coupled to thememory and configured to: identify, by the distributed system, aplurality of electronic devices capable of synchronizing applicationstate data; run, by the distributed system, a first instance of anapplication at a first device of the plurality of the electronicdevices; run, by the distributed system, a second instance of theapplication at a second device of the plurality of the electronicdevices; determine, by the distributed system, a first sync event thatoccurs in the first device; store, by the distributed system, a firststate data of the first instance of the application; determine, by thedistributed system, a second sync event that occurs in the seconddevice; store, by the distributed system, a second state data of thesecond instance of the application; receive, by the distributed system,a selection of one of the first state data and the second state data asa final state data; determine, by the distributed system, a third deviceto which the final state data is to be synchronized; and send, by thedistributed system, the final state data of the application to the thirddevice.
 16. The distributed system of claim 15, wherein the first deviceis a smartphone, wherein the second device is a tablet computer.
 17. Thedistributed system of claim 15, wherein the first state data of thefirst instance of the application is stored in a cloud storage server.18. The distributed system of claim 15, wherein the first sync eventcomprises at least one of: a closure of the application at the firstdevice; a pause of the application at the first device; continuousoperation of the application for a preconfigured period of time at thefirst device; or a switch from the application to an another applicationat the first device.
 19. The distributed system of claim 15, wherein thesecond sync event comprises at least one of: a closure of theapplication at the second device; a pause of the application at thesecond device; a continuous operation of the application for apreconfigured period of time at the second device; or a switch from theapplication to an another application at the second device.